What is curtain walling?

Curtain walling is a non-structural external cladding system, typically aluminium-framed with glazed or opaque infill panels. It hangs from the building's structural frame like a curtain and must resist wind loads, thermal movement and water penetration while meeting Part L thermal and Part B fire requirements.

How much does curtain walling cost per m² in the UK?

In 2026, stick-system curtain walling with double-glazed units typically costs £400-£600/m² supply and install. Unitised systems range from £600-£900/m². Point-fixed structural glass is the most expensive at £700-£1,100/m². Costs vary with height, access, specification and finish.

What U-value does curtain walling need under Part L?

Under Part L 2021, curtain walling in new non-domestic buildings should achieve a U-value of 1.6 W/m²K or better as a maximum limiting standard. The notional building specification targets 1.3 W/m²K. Enhanced thermal breaks and triple glazing can achieve below 1.0 W/m²K.

What is the difference between stick and unitised curtain walling?

Stick systems are assembled on site piece by piece from mullions, transoms and glazing panels. Unitised systems arrive as pre-assembled factory-made modules that are craned into place. Unitised is faster on site but more expensive, making it suited to large-scale commercial projects.

How heavy is curtain walling?

A typical double-glazed curtain walling system weighs approximately 35-45 kg/m², while triple-glazed systems weigh 50-60 kg/m². The structural engineer must account for this dead load plus wind loading when designing the primary structure and fixing brackets.

TradeCalculator.co.uk

Curtain Walling Calculator

Estimate costs, panel quantities, U-values and weight for aluminium curtain walling systems. Covers stick, unitised, structural silicone and point-fixed systems.

Facade Width

Total horizontal span

Facade Height

Total vertical height

System TypeStick is most common for smaller projects

Glazing TypeTriple glazing for enhanced thermal performance

Price per m²

Supply and install cost per m²

Spandrel Panel %

Opaque spandrel panels as % of facade

How We Calculate This

This calculator estimates costs, panel quantities and thermal performance for aluminium curtain walling facades.

The formula

Total cost = Facade area (m²) × Price per m² × Finish multiplier

Facade area = width × height
Panel count = total area ÷ typical panel size
Weight = area × weight per m² (40-55 kg depending on glazing)

Part L compliance

Limiting standard: 1.6 W/m²K
Notional building: 1.3 W/m²K target

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.